Parameter Estimation And Study Of An Item Response Model That Incorporates Response Time

Content: Basing on psychology, in this paper main research of response time and IRT are briefly reviewed firstly, then 4PLRT model is introducted.4PLRT model is worth research and developing more as a psychometric model which combines response time and IRT. The study of estimating all parameters of the model in the same time is precondition, but it has not been started in our country.This paper summarizes all methods of IRT parameter estimation, and presents many estimation scenarios on the basis of the character of IRT model. Basing on careful analysis, comparing and breaking traditional thinking, the question of estimating 4PLRT model's parameter is changed into the problem of two aiming function's optimizations. MMLE/GA is used by MATLAB. Because GA is a parallel random optimization algorithm, this method needn't differential coefficient, initial value and transcendental distribution information, and it's widely useful. The traditional estimation method hasn't these excellences due to Newton iterative.Further more, the estimation program is examined and discussed by many Mont Color simulations. The program is exact, widely useful accord ABS and RMSD. Moreover, the estimation by 4PLRT model is exacter than the estimation by 3PL model when the answers are simulated by 4PLRT.Final, conclusion about this research is presented and directions for further study are suggested.